Zyxel · Multiple Products

CVE-2020-29583

Zyxel Multiple Products Use of Hard-Coded Credentials Vulnerability

Evidence

Source & freshness

Full source status →

CISA KEV catalog Core KEV record

CVE, vendor/product, CISA dates, ransomware status, description, required action, and notes.

Catalog 2026.07.24 · Retrieved 2026-07-25 20:49 UTC Open official CISA feed ↗

MITRE CWE catalog CWE context

CWE names and plain-language weakness descriptions. CISA supplies the CWE assignment itself.

Retrieved 2026-07-25 20:59 UTC Open official MITRE CWE catalog ↗

National Vulnerability Database NVD technical context

CVSS metrics, NVD timeline, and related NVD record data are stored locally.

Retrieved Jul 25, 2026, 08:49 PM UTC Open NVD record ↗

CISA KEV record

CISA date added: 2021-11-03
CISA due date: 2022-05-03
Known ransomware use: Unknown

NVD risk context

9.8 CRITICAL

CVSS is a technical severity score. CISA’s KEV status remains the evidence that this vulnerability is known to be exploited.

View NVD record ↗

Attack vector

Network

The vulnerable service can be reached remotely over a network.

Attack complexity

Low

Exploitation does not require unusual conditions beyond normal attacker control.

Privileges required

None

The attacker does not need an existing account or privileges.

User interaction

None

No action by another user is required.

Description

Zyxel firewalls (ATP, USG, VM) and AP Controllers (NXC2500 and NXC5500) contain a use of hard-coded credentials vulnerability in an undocumented account ("zyfwp") with an unchangeable password.

Required action

Apply updates per vendor instructions.

NVD reference index

Vendor and remediation references

NVD has tagged these sources as vendor advisories, patches, mitigations, or release notes.

https://businessforum.zyxel.com/discussion/5252/zld-v4-60-revoke-and-wk48-firmware-release ↗
Release Notes NVD reference source: cve@mitre.org
https://businessforum.zyxel.com/discussion/5254/whats-new-for-zld4-60-patch-1-available-on-dec-15 ↗
Release Notes NVD reference source: cve@mitre.org
https://www.zyxel.com/support/CVE-2020-29583.shtml ↗
Vendor Advisory NVD reference source: cve@mitre.org
https://www.zyxel.com/support/security_advisories.shtml ↗
Vendor Advisory NVD reference source: cve@mitre.org

Other NVD references (4)

http://ftp.zyxel.com/USG40/firmware/USG40_4.60%28AALA.1%29C0_2.pdf ↗
Broken Link NVD reference source: cve@mitre.org
https://www.eyecontrol.nl/blog/undocumented-user-account-in-zyxel-products.html ↗
Broken LinkThird Party Advisory NVD reference source: cve@mitre.org
https://www.secpod.com/blog/a-secret-zyxel-firewall-and-ap-controllers-could-allow-for-administrative-access-cve-2020-29583/ ↗
ExploitThird Party Advisory NVD reference source: cve@mitre.org
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-29583 ↗
US Government Resource NVD reference source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

MITRE CWE context

CWE classification

CWE-522 Insufficiently Protected Credentials

The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval.

View official MITRE CWE details ↗

NVD record timing

NVD record timeline

These dates describe NVD’s record, not CISA’s KEV addition or remediation due date.

NVD published: Dec 22, 2020, 10:15 PM UTC
NVD last updated: Jun 17, 2026, 03:11 AM UTC

Advanced: view the technical CVSS vector

This standardized code is intended for security tools and technical analysts. The plain-language risk summary above explains its main points.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

View NVD record ↗

CISA notes

https://nvd.nist.gov/vuln/detail/CVE-2020-29583

https://nvd.nist.gov/vuln/detail/CVE-2020-29583